问题 填空题

自然界中人与动物的生存都离不开氧气。

(1)核潜艇舱室中氧气的来源主要靠电解水制得(原理如图)。

①正极收集的气体是____。

②A试管和B试管中收集到的气体的体积比约等于______。

③水是由__________组成的。

(2)过氧化钠(Na2O2)可作为宇航员供氧剂。它与人体呼出的二氧化碳气体反应生成氧气和另一种能用于造纸、纺织等生产的物质,这种物质的俗名为____。

(3)亚氯酸钠(NaClO2)不仅可以制得氧气,还可用于漂白杀菌,其中氯元素的化合价为____。

(4)过氧化钙(CaO2)用于鱼池供氧剂,同时有熟石灰生成。

①写出过氧化钙与水反应的化学方程式________。

②现将7.2g过氧化钙放入盛有36.0g水的烧怀中,使之充分反应后烧杯内混合物中氧元素的质量分数____(结果保留一位小数)。

答案

(1)①氧气或O2;②2:1;③氢、氧两种元素

(2)纯碱或苏打

(3)+3

(4)①2CaO2+2H2O==2Ca(OH)2+O2↑;②80.8%

阅读理解

There is a definite possibility that the climate of the world may be changing. Some scientists imagine that this could even mean the beginning of another ice age. The effects of such a change in climate on the human population of the world would be startling(惊人的).

Recent research suggests that the general warming trend of the past hundred years or so may be coming to an end. During the past ten years, meteorologists tell us the average temperature of the Earth has dropped about one degree Fahrenheit. This does not seem like much, but it could have effects on wind and rain patterns which influence the overall weather picture. If these patterns change a lot, it could mean that certain regions of the world may continue to have long droughts while others will possibly suffer from widespread flooding.

What regulates(调节)the climate is not exactly known. Meteorologists believe that clouds may be an important factor in regulating the amount of solar heat held by the Earth, which in turn determines the temperature of the planet. Another possibility is that man’s industrial and agricultural methods may be affecting the natural weather patterns. However, the weather is not understood well enough for scientists to say for certain what is happening to the climate and what side effects this will actually have on the world’s population.

小题1:According to the passage, the climate of the world seems to    .

A.be getting colder

B.be getting warmer

C.remain the same in the past ten years

D.have good effects on the world’s population小题2:Which of the following is TRUE according to the passage?

A.Man’s activities have no effect on the climate.

B.Another ice age will come soon.

C.People don’t care about the changing climate.

D.Scientists are not yet sure about the reason for the changing climate.小题3:A meteorologist is a person who        .

reads weather forecasts on radio or television 

B. thinks there will be another ice age

C. studies and knows about the weather       

D. believes there will be widespread flooding

小题4: Which of the following may be the factor(s) that affect(s) the natural weather patterns?

A.Clouds.

B.The amount of heat the Earth receives.

C.Man’s industrial and agricultural methods.

D.All of the above.小题5:The best title for the passage would be         .

A.Droughts and Floods.

B.Meteorologists

C.The Changing Climate

D.Solar Heat

单项选择题